1. Field of Invention
The present invention relates to a system for cleaning pressurized containers having chemicals contained therein. Specifically, the present invention relates to a system for cleaning pressurized containers such as, for example, rail tank cars, mobile tanks or the like. Further, the chemicals may comprise any material stored under pressure that may be difficult to collect and dispose of due to the hazardous characteristics thereof. Moreover, the chemicals may further be highly reactive to moisture and may form damaging acids or other reaction products when contacting water.
2. Background of the Invention
It is, of course, generally known to store and/or transport chemicals having hazardous characteristics via pressurized containers. Further, it is also generally known to clean these containers using a variety of methods and systems. In the past, cleaning pressurized containers entailed venting excess gaseous material to the atmosphere. Further, unpressurized containers contained bottom hatches or valves for draining liquid chemicals. However, many hazardous chemicals escaped into the environment thereby causing health risks for humans, vegetation and wildlife. With the advent of environmental standards and compliance, however, venting or draining hazardous chemicals to the environment has generally become illegal.
Moreover, some chemicals that may be stored within pressurized containers may be highly reactive in the presence of water and may form acids that may be damaging to equipment as well as the environment. Although a flare may be useful to dispose of chemicals that are flammable, some chemicals do not incinerate easily or may form extremely hazardous substances upon incineration. Typically, scrubbers or sparge tanks are necessary to dispose of these chemicals or byproducts of these chemicals.
While some of the gases contained within the containers may be relatively easy to recover and dispose of by venting the pressurized containers to a flare or to a sparge tank, it is difficult to remove all of the gases contained therein. Further, liquid product may remain inside a container after cleaning. Typical systems and methods of cleaning pressurized containers may involve injecting the container with a quantity of steam that may aid in bringing the liquid chemicals to the gaseous phase and removing the steam/gaseous chemical product combination for incineration or disposal. However, problems may occur using steam to remove chemicals from pressurized containers since steam may condense within the container forming liquid water or ice. The liquid water or ice may mask the presence of the chemicals from detectors or otherwise encapsulate the chemicals. Further, the liquid water or ice may interfere with the removal of the chemicals from the container. Moreover, liquid water or steam may react with certain chemicals, such as for example, chlorine gas or sulfur dioxide gas to form hazardous byproducts, such as acids, that may damage equipment or the environment if released. For example, chlorine gas and sulfur dioxide gas may react with water according to the following reaction:
Cl2+H2Oxe2x86x92HCl+HOClxe2x80x83xe2x80x831.
2 SO2+2 H2O+O2xe2x86x922 H2SO4xe2x80x83xe2x80x832.
In addition, steam or liquid water may be difficult to remove from the container since water droplets may stick to the inside surfaces of the container, piping and/or equipment. A further step would be required for drying the container and/or the equipment, thereby requiring additional time, equipment and expense.
Another method of removal may include entering the container to manually remove the chemical and/or any other debris, such as, for example, scaling, that may be contained within the container. While this may be a relatively thorough way to remove the chemical from the container, it may be very dangerous, as it requires an individual to actually enter the container thereby exposing the individual to any chemicals that may be contained therein. Further, by opening the container, there may be a significant risk that some of the chemicals may escape into the environment.
Therefore, an improved system of cleaning pressurized containers is necessary. Particularly, a system is needed that overcomes the problems associated with typical cleaning systems. Further, a system is needed that cleanly and efficiently removes chemicals from a pressurized container and transports the waste product to a proper disposal system such as a flare or a reaction tank to incinerate or otherwise safely dispose of the chemicals.
The present invention relates to a system for cleaning a pressurized container having chemicals therein. More specifically, the present invention allows mobile containers such as, for example, rail tank cars, to be cleaned safely and efficiently without risking exposure of the chemicals to people or the environment. The invention entails injecting heated and pressurized nitrogen gas or ambient air into the container thereby purging the container of any chemical therein and forming a nitrogen/chemical mixture. The nitrogen/chemical mixture may then be sent to a flare for incineration or a reaction tank for neutralization of the chemical. Further, the heated nitrogen gas may aid in pulling the chemical out of the container and transporting the chemical to the flare for incineration. In addition, a vacuum pump may be utilized to further aid in the removal of the nitrogen/chemical mixture from the container.
To this end in an embodiment of the present invention, a system for cleaning pressurized containers containing chemicals is provided. The system comprises: a container having a quantity of chemicals therein wherein the container has a plurality of valves for attaching a plurality of pipes thereto; a nitrogen gas storage tank wherein the nitrogen gas storage tank is attachable to a first valve on the container; a heat exchange means wherein the first pipe is heated by the heating means; a tank containing a caustic material connected to the container via a pipe; and a vacuum pump disposed between the container and the tank.
Further, a system is provided wherein the plurality of valves regulates a flow of nitrogen gas from the nitrogen gas storage tank and the container. Still further, the container is a railcar. Alternatively, the container is disposed on a vehicle.
Moreover, the present invention provides a system that further comprises a heating means connected to the heat exchange means for feeding a fluid to the heat exchange means for heating nitrogen gas that flows through the heat exchange means. Moreover, the system comprises a nitrogen vaporizer attached to a second section of the first pipe for vaporizing the nitrogen from the nitrogen storage tank.
In addition, a pipe within the container is attached to a valve wherein the first pipe within the container extends to a bottom of the container. Additionally, a pipe within the container is attached to a valve and extends partially within the container.
In a further embodiment of the present invention, the system comprises a controller interconnected with the plurality of valves for controlling the opening and closing of the valves. Moreover, the controller controls the vacuum pump. Moreover, the controller controls the opening and closing of the plurality of valves in synchronization with the vacuum pump.
In addition, the system further comprises a gauge attached to the container for measuring the internal pressure of the container. In addition, the tank comprises a quantity of a material selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium carbonate, calcium hydroxide, sodium sulfite, sodium thiosulfite, ferrous chloride and solid bed absorbents. Further, the tank neutralizes chlorine gas and sulfur dioxide gas. Still further, a first pipe extends from the container to the vacuum pump and a second pipe extends from the vacuum pump to the tank containing the caustic material.
In an alternate embodiment of the present invention, a system for cleaning pressurized containers containing chemicals is provided. The system comprises: a container having a quantity of chemicals therein wherein the container has a plurality of valves for attaching a plurality of pipes thereto; an intake means for blowing air into the container via a first pipe; a heating means wherein the first pipe is heated by the heating means; a tank containing a caustic material connected to the container via a pipe; and a vacuum pump disposed between the container and the tank having caustic material contained therein. Moreover, the intake means comprises a fan. In addition, the air is regulated into the container via a first valve wherein the first valve is connected to a controlling means. Moreover, a pressure gauge is attached to one of the plurality of valves for measuring the pressure within the tank. In addition, a control panel having a plurality of switches for controlling the system.
In a further embodiment of the present invention, the tank comprises a quantity of a material selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium carbonate, calcium hydroxide, sodium sulfite, sodium thiosulfite, ferrous chloride and solid bed absorbents. Moreover, the tank neutralizes chlorine gas and sulfur dioxide gas. Further, a first pipe extends from the container to the vacuum pump and a second pipe extends from the vacuum pump to the tank containing the caustic material.
It is, therefore, an advantage of the present invention to provide a system for cleaning a pressurized container having a quantity of chemicals therein that safely and efficiently removes chemicals from the container. Moreover, it is advantageous that the present invention removes chemicals from the container without risking exposure to people or the environment.
Further, it is an advantage of the present invention to provide a system for cleaning a pressurized container having a quantity of chemicals therein that allows the chemicals to be removed without causing damage to the container by freezing the container or pipes connected thereto. In addition, an advantage of the present invention is that the heated nitrogen gas used to remove the product will not condense within the container and therefore will not mask the presence of the chemicals therein.
Another advantage of the present invention is to provide a system for cleaning a pressurized container having a quantity of chemicals therein that is largely automatic and therefore allows an individual to monitor the process without exposing the individual to the chemicals. Additionally, an advantage of the present invention is that a plurality of types of containers may be cleaned using the system and method defined herein, including, but not limited to, rail tank cars and other like containers.
A still further advantage of the present invention is to provide a system for cleaning a pressurized container having a quantity of chemicals therein that utilizes a vacuum pump to remove chemicals from the container and to create a vacuum in the container to aid in the injection of heated nitrogen gas to the container.
Additional features and advantages of the present invention are described in and will be apparent from, the detailed description of the presently preferred embodiments and from the drawings.